[Help] Filtering a MPMediaQuery Further. [WTF]

I have succeeded in using MPMediaQuery's, Table Views and several other things to search the iPod Library with my app, but I now need to implement a search function where I need to press a button (A-Z) and have the Table View pop-up with all Artists or Songs or Albums starting with the pressed letter. I have the basics of it working, but I can never get the "Artists starting with "LETTER"" to show right, it just returns EVERY song with the letter in it somewhere. And that's a fair few on a 16GB iPhone.